iOS touch recognition on UI has odd delays

I built a simple 2D game with Unity which runs totally fine on my computer with ~200 fps normally and ~60 on mobile. Unfortunately, on mobile, UI is behaving strangely. It takes multiple taps to a button or event trigger to activate it and in the case that one event is triggered (ex. PointerDown) another will not activate (ex. PointerUp). However, the game runs smoothly and when I can actually move a ScrollRect or press a button, it all works normally.

Any idea what is going on? I can clarify if you need to know more information.

Are you using the UI introduced in 4.6? If so, make sure that the checkbox for standalone events labeled as "Allow Activation on Mobile " is unchecked.